Katy Perry deliberately appeals to the trend of a generation of young women who are completely aware that straight men in general find girls kissing girls to be hot, and do it for the sole purpose of turning men on.
Because women are not individuals, so it's OK to make judgements and generalise about an entire generation. Oh, and straight men are the centre of the universe, around which all things revolve. Again.
Of course it's ok to generalize to discern a trend.
Especially it's ok to generalize about 'the average young person' who tend to be more impressionable than 'the average person.' For that matter, everyone is unique, sure, but not in all ways. Sometimes generalizing a trait is ok if the generalization is obvious.
You know, as long as it isn't a research paper and we're all informal and stuff. "Trends" in research papers are generally empirical, instead of merely an inferred tendency of one population compared to another population (i.e. the generations previous).
On the same note, of course it's not true that straight men are the center of the universe, but they might as well be for most straight girls. Half of that is hormones, half of that is conditioning. Much like straight boys. Usually it is grown out of...but if the success of
Teenage Dream is any indication, we *really* (and for artificial reasons) glorify youth in this culture.
(Aw yeah, bringing it back to the Perry.)